This invention relates to an apparatus for opening and cleaning fiber material, particularly cotton. The apparatus is of the type which has at least three clothed rolls arranged downstream of a fiber feeder. At least two of the clothed rolls are each associated with at least one mote knife and a waste discharge opening bounded by the mote knife. The centrifugal force at the circumference of any one of the clothed rolls is greater than the clothed roll or clothed rolls upstream thereof. The clothed rolls are arranged in a series and each clothed roll cooperates with the immediately preceding clothed roll as a doffer and opening roll.
In a known apparatus of the above-outlined type there are provided three serially arranged clothed rolls in which the diameter of the first clothed roll and the adjoining clothed roll are different. The second clothed roll is surrounded by a housing which is void of waste discharge openings or mote knives. It is a disadvantage of this arrangement that the unlike roll diameters result in certain additional manufacturing costs.